Inverter device

ABSTRACT

An inverter device including a plurality of switching elements that convert electric power between DC power and AC power, a base plate that includes a surface on which the switching elements are placed, AC terminals through which AC power is input and output to and from an external device and which are electrically connected to the switching elements, and a capacitor that smoothes DC power. The AC terminals are disposed to protrude from the base plate perpendicular to the surface in a first reference direction. The capacitor is disposed in a rectangular area so that long sides of the rectangle are parallel to the first reference direction in plan view, and is set adjacent to a base disposition area, in which the base plate and the AC terminals are disposed in a second reference direction that is a direction perpendicular to the first reference direction.

INCORPORATION BY REFERENCE

The disclosure of Japanese Patent Application No. 2011-080707 filed onMar. 31, 2011, including the specification, drawings and abstractthereof, is incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an inverter device including aplurality of switching elements that convert electric power between DCpower and AC power, a base plate that includes an element placingsurface on which these plurality of switching elements are placed, ACterminals through which AC power is input and output to and from anexternal device and which are electrically connected to the switchingelements, and a capacitor that smoothes DC power.

2. Description of the Related Art

In recent years, a hybrid vehicle or an electric vehicle, which includesa rotary electric machine as a driving power source, has come into thespotlight in terms of energy saving or the reduction of environmentalburden. There are many cases where a DC power source such as ahigh-voltage battery is generally provided and the rotary electricmachine is driven by AC power in the hybrid vehicle or the like. Forthis reason, the hybrid vehicle or the like is provided with an inverterdevice between the DC power source and the rotary electric machine.Meanwhile, the inverter device is not limited to the use for a hybridvehicle or the like, and may generally be required even for airconditioning equipment, electric power controllers, or the like.

A device disclosed in, for example, the following JP-A-2008-29094 hasalready been known as the above-mentioned inverter device. Hereinafter,names and reference numerals of corresponding members disclosed inJP-A-2008-29094 will be quoted in square brackets in the description ofthe section of the background art. As shown in FIGS. 2 and 3 ofJP-A-2008-29094, this device includes a base plate [motor substrate 120and cooling fins 12] on which a plurality of switching elements[MOS-FETs 111a to 111f] are provided, AC terminals [AC terminals 71, 72,and 73] through which AC power is input and output to and from anexternal device [motor generator 940], and capacitors [electrolyticcapacitors 21, 22, and 23] that smooth DC power. In this device, thecapacitors, the base plate, and the AC terminals are sequentiallyarrayed in a predetermined direction (a vertical direction in FIG. 3 ofJP-A-2008-29094) in plan view seen in a direction perpendicular to anelement placing surface on which the plurality of switching elements areplaced. Further, the AC terminals are disposed so as to protrude from acase [housing 10], which receives the capacitors and the base plate, inthe predetermined direction. Meanwhile, one (positiveelectrode-secondary DC terminal 61) of the power supply terminals,through which DC power is input and output to and from a DC powersource, is also disposed so as to protrude from the case in thepredetermined direction.

It is preferable that the entire size of the inverter device begenerally reduced as much as possible when the inverter device isformed. In particular, since there is a limitation on the mounting ofthe inverter device on a vehicle in the use for a hybrid vehicle or thelike, the above-mentioned request is particularly significant. In thisrespect, dead spaces are formed between the AC terminals and the powersupply terminal, which protrude from the case in the predetermineddirection, in the device of JP-A-2008-29094. As a result, there has beena problem in that the entire size of the inverter device is increased.Further, since the capacitors significantly protrude from the base platein the direction perpendicular to the element placing surface as shownin FIG. 5 of JP-A-2008-29094 in the device of JP-A-2008-29094, theentire size of the inverter device has been increased due to thisaspect.

SUMMARY OF THE INVENTION

Accordingly, it is desirable to provide an inverter device of which theentire size can be reduced.

According to the invention, there is provided an inverter deviceincluding a plurality of switching elements that convert electric powerbetween DC power and AC power, a base plate that includes an elementplacing surface on which these plurality of switching elements areplaced, AC terminals through which AC power is input and output to andfrom an external device and which are electrically connected to theswitching elements, and a capacitor that smoothes DC power. Thestructure of the inverter device is characterized in that the ACterminals are disposed so as to protrude from the base plate in apredetermined first reference direction in plan view seen in a directionperpendicular to the element placing surface; the capacitor is disposedin a capacitor disposition area that is set in a rectangular shape inthe plan view; and the capacitor disposition area is set so that longsides of the rectangular shape are parallel to the first referencedirection in the plan view, and is set adjacent to a base dispositionarea, in which the base plate and the AC terminals are disposed, in asecond reference direction that is a direction perpendicular to thefirst reference direction.

Meanwhile, the “rectangular shape” is used as a concept that representsa shape regarded as a substantially rectangular shape as a whole, eventhough there are some deformed portions.

According to the characteristic structure, the base disposition area, inwhich the base plate and the AC terminals disposed so as to protrudefrom the base plate in the first reference direction are disposed, andthe rectangular capacitor disposition area, in which the capacitor isdisposed and which has long sides parallel to the first referencedirection, are disposed adjacent to each other in the second referencedirection in plan view seen in a direction perpendicular to the elementplacing surface. That is, the base plate, the AC terminals, and thecapacitor are not sequentially arrayed in the first reference direction,and the capacitor is disposed adjacent to the base plate and the ACterminals in the second reference direction. Accordingly, it is possibleto compactly dispose all of the base plate, the AC terminals, and thecapacitor in an area, which has a rectangular shape in plan view, bysetting the positions of both end portions of the capacitor dispositionarea in the first reference direction in accordance with the positionsof both end portions of the base disposition area in the first referencedirection. Therefore, it is possible to provide an inverter device ofwhich the entire size can be reduced.

Meanwhile, the capacitor has a relatively large degree of freedom in thedesign of the size and shape thereof, as compared to the AC terminalsthrough which AC power is input and output to and from the externaldevice or the base plate on which the switching elements are provided.For this reason, it is possible to adjust the size and shape of thecapacitor in accordance with the size and shape of the capacitordisposition area, so that the above-mentioned inverter device can beappropriately provided.

Here, the inverter device may further include a control board that isprovided with at least a drive circuit for the switching elements. Thecontrol board may be adjacent to both the capacitor disposition area andthe base disposition area in a perpendicular reference direction, whichis a direction perpendicular to the element placing surface, and may bedisposed at a position overlapping both the capacitor disposition areaand the base disposition area in the plan view.

Meanwhile, in regard to the disposition of two members, “overlap whenseen in a predetermined direction” means that a viewing point where thetwo members overlap each other is present in at least a part of an areawhen the predetermined direction is used as a viewing direction and theviewing point is moved in each direction perpendicular to the viewingdirection.

According to this structure, the control board is disposed adjacent toboth the capacitor disposition area and the base disposition areawithout being significantly distant from both the capacitor dispositionarea and the base disposition area in the perpendicular referencedirection. Accordingly, it is possible to suppress the increase of thesize of the inverter device in the perpendicular reference direction.Further, since the control board is disposed at the position thatoverlaps both the capacitor disposition area and the base dispositionarea in the plan view (when seen in the perpendicular referencedirection), all of the main components, which also include the controlboard, of the inverter device can be easily disposed so as to bereceived in the area that has a rectangular shape in the plan view.

Furthermore, the length of the capacitor disposition area in the firstreference direction may be set so as to be longer than the length of thebase plate in the first reference direction, and the AC terminals may bedisposed in an area overlapping the capacitor disposition area when seenin the second reference direction.

According to this structure, the AC terminals are disposed so as to bereceived in the area that is formed due to the difference between thelength of the capacitor disposition area and the length of the baseplate in the first reference direction. Accordingly, it is possible tocompactly dispose all of the base plate, the AC terminals, and thecapacitor.

Moreover, heat dissipating fins may be provided on the side of the baseplate opposite to the element placing surface, and a connecting support,which supports electrical connection members electrically connecting atleast the switching elements to the AC terminals, may be provided on thesame side of the base plate as the element placing surface; the basedisposition area may be set so as to include disposition areas of theheat dissipating fins and the connecting support; and the length andposition of the capacitor disposition area in a perpendicular referencedirection, which is a direction perpendicular to the element placingsurface, may be set so as to correspond with the length and position ofthe base disposition area in the perpendicular reference direction.

Meanwhile, “correspond” is used as a concept representing that events(which include length and a position), that is, objects to be comparedare substantially the same as each other. That is, “correspond” includesnot only a state where events, that is, objects to be compared areexactly the same as each other but also a state where there aredifferences between these events. For example, “correspond” alsoincludes a state where differences between the events, that is, theobjects to be compared are sufficiently small as compared to all of theevents and the events are substantially the same as each other so thatperipheral portions can be designed or manufactured, or a state wherethere are differences caused by allowable errors in design ormanufacture.

According to this structure, it is possible to efficiently dissipateheat from the base plate by the heat dissipating fins, so that it ispossible to efficiently cool the switching elements. Further, it ispossible to electrically connect the switching elements to the ACterminals while appropriately supporting the electrical connectionmembers by the connecting support.

Furthermore, in the above-mentioned structure, the base disposition areais set so as to include disposition areas for the heat dissipating finsand the connecting support, and the length and position of the capacitordisposition area in the perpendicular reference direction are set so asto correspond with the length and position of the base disposition areain the perpendicular reference direction. For this reason, in terms of apositional relationship in the direction along the perpendicularreference direction, the capacitor can be disposed so as to be receivedin the area that is occupied by all of the base plate, the AC terminals,the heat dissipating fins, and the connecting support. Therefore, all ofthe base plate, the AC terminals, the heat dissipating fins, theconnecting support, and the capacitor are easily disposed so as to bereceived in the area, which has a rectangular shape when seen in atleast one of the first and second reference directions, without deadspaces. As a result, it is possible to provide an inverter device ofwhich the entire size can be further reduced.

Moreover, the length and position of the capacitor disposition area inthe first reference direction may be set so as to correspond with thelength and position of the base disposition area in the first referencedirection.

According to this structure, in terms of a positional relationship inthe direction along the first reference direction, the capacitor can bedisposed so as to be received in the area that is occupied by all of thebase plate and the AC terminals. Accordingly, all of the base plate, theAC terminals, and the capacitor can be disposed so as to be received inthe area, which has a rectangular shape in plan view, without deadspaces. Therefore, it is possible to successfully provide an inverterdevice of which the entire size can be further reduced.

Further, the inverter device may further include power supply terminalsthrough which DC power is input and output to and from a DC powersource, DC terminals through which DC power is input and output to andfrom the switching elements, and capacitor connecting members thatelectrically connect the power supply terminals to the DC terminalsthrough the capacitor. The control board may further be provided with avoltage detecting circuit that detects a voltage between both electrodesof the capacitor. Branch connection portions, which may be branched fromthe capacitor connecting members and extend in the perpendicularreference direction, may be connected to the voltage detecting circuitwhile passing through the control board.

According to this structure, the branch connection portions, which arebranched from the capacitor connecting members electrically connectingthe power supply terminals to the DC terminals, extend in theperpendicular reference direction and pass through the control board.Accordingly, it is possible to connect the capacitor connecting membersto the voltage detecting circuit over a short distance.

Furthermore, the power supply terminals and the DC terminals may bedisposed at positions that are different in the first referencedirection and point-symmetrical to each other with respect to the centerof gravity of the shape of the capacitor disposition area in the planview.

Meanwhile, “point-symmetry” is used as a concept that representssymmetry regarded as substantially point-symmetry as a whole even thoughthere are some positional deviations.

In the invention, it is possible to set the positions of both endportions of the capacitor disposition area in the first referencedirection in accordance with the positions of both end portions of thebase disposition area in the first reference direction. For example, itis possible to make the length and position of the capacitor dispositionarea in the first reference direction correspond with the length andposition of the base disposition area in the first reference direction.In this case, the area, in which the base plate is disposed, of the basedisposition area in the first reference direction except for the ACterminal portions is an area that occupies only a predetermined range onone side of the capacitor disposition area. For this reason, the centerof gravity of the shape of the base plate in plan view and the center ofgravity of the shape of the capacitor disposition area (and thecapacitor) in the plan view correspond to positions that are differentfrom each other in the first reference direction. Meanwhile, consideringthe design or the like of the electrical connection members thatelectrically connect the DC terminals to the switching elements, it ispreferable that the DC terminals, through which DC power is input andoutput to and from the switching elements, be disposed at the positionof the center of gravity of the base plate in the first referencedirection. In this case, the DC terminal and the center of gravity ofthe capacitor disposition area (and the capacitor) correspond topositions that are different from each other in the first referencedirection.

In this structure, according to the above-mentioned structure, the powersupply terminals and the DC terminals are disposed at positions that aredifferent in the first reference direction and point-symmetrical to eachother with respect to the center of gravity of the capacitor dispositionarea in the plan view. Accordingly, in the structure where a pluralityof capacitor elements are connected between the power supply terminalsand the DC terminals, it is possible to make the lengths of theelectrical connection paths, which pass through the respective capacitorelements and the capacitor connecting members between the power supplyterminals and the DC terminals, correspond with each other. Accordingly,it is possible to substantially equalize the currents that flow throughthe respective capacitor elements. Further, since the amount of heatgenerated by the respective capacitor elements is also substantiallyequalized due to this, it is possible to reduce the size of each of thecapacitor elements and thus to reduce the entire size of the inverterdevice and the capacitor.

Furthermore, the plurality of switching elements may form an invertercircuit. The inverter circuit may have a three-leg structure includingthree legs that include switching elements forming upper stage armsconnected to the side of a positive electrode and switching elementsforming lower stage arms connected to the side of a negative electrode.A direction in which the upper and lower stage arms of each of the legsare connected to each other may be a direction along the first referencedirection, and the three legs may be sequentially arrayed in the secondreference direction.

According to this structure, it is possible to convert electric powerbetween DC power and three-phase AC power by the inverter circuit havingthe three-leg structure.

In this case, in the above-mentioned structure, all of the direction inwhich the upper and lower stage arms of each of the legs are connectedto each other and a direction in which the switching element and the ACterminal of each of the legs are connected to each other are thedirection along the first reference direction. Accordingly, it ispossible to simplify the shapes of the electrical connection members,which electrically connect the switching elements to the AC terminals,into the shape close to the shape of a straight line. Further, since itis possible to make the shapes of the electrical connection members forthe respective phases correspond with each other, it is possible tosimplify the disposition of the electrical connection members for therespective phases to the AC terminals.

Furthermore, since the three legs of which the upper and lower stagearms are disposed in the first reference direction are sequentiallyarrayed in the second reference direction, all of a direction in whichthe upper stage arm of the respective legs are connected to each other,a direction in which the lower stage arm of the respective legs areconnected to each other, and a direction in which the legs are connectedto the positive or negative electrodes of the DC terminals disposed onthe side of the capacitor are the direction along the second referencedirection. Accordingly, it is possible to simplify the shapes of theelectrical connection members, which electrically connect the switchingelements to the DC terminals, into the shape close to the shape of astraight line. Further, since it is possible to make the shapes of theelectrical connection members for the respective phases correspond witheach other, it is possible to simplify the disposition of the electricalconnection members for the respective phases to the DC terminals.

Moreover, the upper and lower stage arms may be disposed so that alongitudinal direction of each of the upper and lower stage arms is adirection along the first reference direction.

According to this structure, it is possible to reduce the lengths of theelectrical connection members for the respective phases in the secondreference direction as compared to the case where the upper and lowerstage arms are disposed so that the longitudinal direction of each ofthe upper and lower stage arms is a direction along the second referencedirection. Therefore, it is possible to reduce the electrical resistanceof the electrical connection members for the respective phases servingas the transmission path for DC power, so that it is possible to improveenergy efficiency.

Further, the external device may be a rotary electric machine as adriving power source of a vehicle; heat dissipating fins may be providedon the side of the base plate opposite to the element placing surface;and an extending direction of the heat dissipating fins, which extend inthe shape of a flat plate, may be set so as to be a direction along atravel direction of the vehicle, and the capacitor may be disposedadjacent to the heat dissipating fins on the rear side in the traveldirection of the vehicle.

According to this structure, it is possible to efficiently dissipateheat from the base plate by the heat dissipating fins, so that it ispossible to efficiently cool the switching elements. Furthermore, sincethe heat dissipating fins are provided so as to extend in the shape of aflat plate in the travel direction of the vehicle and the capacitor isdisposed adjacent to the heat dissipating fins on the rear side in thetravel direction of the vehicle, it is possible to efficiently dissipateheat from the heat dissipating fins by travel wind that is generated dueto the forward travel of the vehicle. Moreover, travel wind, which flowsbetween the heat dissipating fins, is appropriately guided to thecapacitor, so that it is also possible to efficiently cool thecapacitor.

Further, a plurality of AC phase-terminals may be provided as the ACterminals and the plurality of AC phase-terminals may be sequentiallyarrayed in the second reference direction; and the second referencedirection may be a direction perpendicular to a rotating shaft of therotary electric machine and the plurality of AC phase-terminals may bedisposed so as to overlap coils of the rotary electric machine when seenin a radial direction of the rotary electric machine.

According to this structure, the plurality of AC phase-terminals as theAC terminals are sequentially arrayed in the direction perpendicular tothe rotating shaft of the rotary electric machine and the plurality ofAC phase-terminals are disposed so as to overlap the coils of the rotaryelectric machine when seen in the radial direction of the rotaryelectric machine. Accordingly, it is possible to connect the pluralityof AC phase-terminals to the coils of the rotary electric machine alongthe radial direction of the rotary electric machine in the shape of astraight line, so that it is possible to electrically connect the ACphase-terminals to the coils by a minimum number of necessary members.Therefore, it is possible to simplify the electrical connectionstructure between the inverter device and the coils of the rotaryelectric machine.

Moreover, the heat dissipating fins may be provided on the side oppositeto the rotary electric machine with respect to the element placingsurface.

According to this structure, as compared to a case where the heatdissipating fins are provided on the same side as the rotary electricmachine with respect to the element placing surface, the heatdissipating fins are not easily affected by heat generated by the rotaryelectric machine and cooling air is easily supplied to the heatdissipating fins. Therefore, it is possible to more efficientlydissipate heat from the base plate by the heat dissipating fins.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a vehicle drive device and an inverterdevice that are mounted on a vehicle;

FIG. 2 is a schematic view showing the structure of an inverter circuit;

FIG. 3 is an exploded perspective view of an inverter module;

FIG. 4 is a plan view of the inverter device when seen in a Z direction;

FIG. 5 is a side view of the inverter device when seen in an Xdirection;

FIG. 6 is a side view of the inverter device when seen in a Y direction;

FIG. 7 is a schematic view showing the configuration of an electricalcircuit that is provided in a capacitor; and

FIG. 8 is a schematic view showing a state where the vehicle drivedevice and the inverter device are mounted on a vehicle.

DETAILED DESCRIPTION OF THE EMBODIMENTS

An embodiment of an inverter device according to the invention will bedescribed with reference to the drawings. In this embodiment, aninverter device 1 of a system, which controls a rotary electric machine3 functioning as a driving power source for the wheels of a hybridvehicle V (which may be simply referred to as a “vehicle V”hereinafter), will be described by way of example. As shown in FIG. 8,the hybrid vehicle V includes an internal combustion engine 61, avehicle drive device 62 including a rotary electric machine 3, and aninverter device 1. The inverter device 1 includes an inverter circuit 7,and controls the rotary electric machine 3 that is an external devicewhen seen from the inverter device 1. Meanwhile, in this embodiment, therotary electric machine 3 is formed of an AC motor that is driven bythree-phase alternating current. The rotary electric machine 3 canfunction as both a motor that is supplied with electric power andgenerates power and a generator that is supplied with power andgenerates electric power. A structure where the vehicle drive device 62(here, a drive device case as a rotary electric machine case thatreceives the rotary electric machine 3) and the inverter device 1 areintegrally fixed to each other as shown in FIG. 1 is employed in thisembodiment.

The inverter device 1 is connected to the rotary electric machine 3 as adriving power source of the vehicle V and a battery 2 as a DC powersource that is an energy source of the rotary electric machine (seeFIGS. 2 and 8). Further, the inverter device 1 includes a plurality ofswitching elements 14 that convert electric power between DC power andAC power, a base plate 11 that includes an element placing surface 11 aon which the plurality of switching elements 14 are placed, rotaryelectric machine-connection terminals 25 that input and output AC powerto and from the rotary electric machine 3, a capacitor 31 that is usedto smooth DC power, power supply terminals 33 that input and output DCpower to and from the battery 2, and a control board 41 that controlsthe operation of at least the switching elements 14. In this structure,the inverter device 1 according to this embodiment has characteristicsin the configuration of the base plate 11, the rotary electricmachine-connection terminals 25, and the capacitor 31. Further, theinverter device 1 according to this embodiment also has characteristicsin the configuration of the respective components in relation to a statewhere the inverter device is mounted on the vehicle V. The inverterdevice 1 according to this embodiment will be described in detail below.

Meanwhile, in this embodiment, the rotary electric machine-connectionterminals 25 correspond to “AC terminals” of the invention. Further, inthe following description, the respective directions, that is, an “Xdirection”, a “Y direction”, and a “Z direction” are defined on thebasis of the element placing surface 11 a except for the case where thedirections are particularly specified and differentiated from eachother. More specifically, directions, which are parallel to the elementplacing surface 11 a and perpendicular to each other, are defined as the“X direction” and the “Y direction”, respectively. In this embodiment, avertical direction in FIG. 4 is the “X direction”. Here, the side closeto the rotary electric machine-connection terminals 25 relative to thebase plate 11 (the lower side in FIG. 4) corresponds to “+X direction”,and the side close to the base plate 11 relative to the rotary electricmachine-connection terminals 25 (the upper side in FIG. 4) correspondsto “−X direction”. Furthermore, a horizontal direction in FIG. 4 is the“Y direction”. Here, the side close to the capacitor 31 relative to thebase plate 11 and the rotary electric machine-connection terminals 25(the left side in FIG. 4) corresponds to “+Y direction”, and the sideclose to the base plate 11 and the rotary electric machine-connectionterminals 25 relative to the capacitor 31 (the right side in FIG. 4)corresponds to “−Y direction”.

Moreover, a direction perpendicular to the element placing surface 11 a(a direction perpendicular to both the X direction and the Y direction)is defined as a “Z direction”. In this embodiment, a vertical directionin FIG. 5 is the “Z direction”. Here, the side close to the controlboard 41 relative to the base plate 11 and the capacitor 31 (the upperside in FIG. 5) corresponds to “+Z direction”, and the side close to thebase plate 11 and the capacitor 31 relative to the control board 41 (thelower side in FIG. 5) corresponds to “−Z direction”. In this embodiment,the X direction, the Y direction, and the Z direction correspond to a“first reference direction”, a “second reference direction”, and a“perpendicular reference direction” of the invention, respectively.

1. Structure of Inverter Circuit

First, the structure of the inverter circuit 7 will be described. Theinverter circuit 7 according to this embodiment includes a plurality of(six in this embodiment) switching elements 14. The switching elements14 are electronic elements that convert electric power between DC powerand AC power, and serve as the core of the inverter circuit 7 and theinverter device 1. As shown in FIG. 2, the inverter circuit 7 is formedof a bridge circuit, two switching elements 14 are connected in seriesbetween the side of a positive electrode P of the battery 2 and the sideof a negative electrode N (for example, the ground side) of the battery2, and three series circuits each of which is formed of two switchingelements are connected in parallel. That is, the inverter circuit 7 hasa three-leg structure including three legs that include the switchingelements 14 forming upper stage arms connected to the side of thepositive electrode P and the switching elements 14 forming lower stagearms connected to the side of the negative electrode N. The legscorrespond to three phases (U phase, V phase, and W phase) of coils(stator coils) 3 b (see FIG. 8) of the rotary electric machine 3,respectively.

In FIG. 2, reference numeral 14 a denotes an upper stage-side switchingelement for a U phase, reference numeral 14 b denotes an upperstage-side switching element for a V phase, and reference numeral 14 cdenotes an upper stage-side switching element for a W phase. Further,reference numeral 14 d denotes a lower stage-side switching element fora U phase, reference numeral 14 e denotes a lower stage-side switchingelement for a V phase, and reference numeral 14 f denotes a lowerstage-side switching element for a W phase. Here, the “upper stage-side”means an arm corresponding to the side of the positive electrode P, andthe “lower stage-side” means an arm corresponding to the side of thenegative electrode N.

Collectors of the upper stage-side switching elements 14 a, 14 b, and 14c for the respective phases are connected to the side of the positiveelectrode P through a fourth bus bar 23 d, and emitters thereof areconnected to collectors of the lower stage-side switching elements 14 d,14 e, and 14 f for the respective phases through bus bars 23 a, 23 b,and 23 c. Moreover, emitters of the lower stage-side switching elements14 d, 14 e, and 14 f for the respective phases are connected to the sideof the negative electrode N through a fifth bus bar 23 e. A diodeelement 15 is connected in parallel between the emitter and thecollector of each of the switching elements 14. An anode of the diodeelement 15 is connected to the emitter of each switching element 14, anda cathode thereof is connected to the collector of each switchingelement 14. The diode element 15 is used as an FWD (Free Wheel Diode).

The respective arms, which include the switching elements (14 a and 14d), (14 b and 14 e), and (14 c and 14 f) making a pair and therespective corresponding bus bars 23 a, 23 b, and 23 c, are connected tothe coils 3 b (see FIG. 8) for the respective phases of the rotaryelectric machine 3 through the rotary electric machine-connectionterminals 25 a, 25 b, and 25 c. Further, gates of the respectiveswitching elements 14 are connected to a drive circuit 43 (see FIG. 5)provided on a control board 41, and are individually subjected toswitching control.

The inverter device 1, which includes the inverter circuit 7, convertsDC power, which is supplied from the battery 2, into three-phase ACpower and supplies the three-phase AC power to the rotary electricmachine 3 by controlling the respective switching elements 14 (forexample, performing the pulse width modulation control or the like ofthe respective switching elements) on the basis of required rotationalspeed and required torque that are required for the rotary electricmachine 3. Accordingly, the power running of the rotary electric machine3 is performed according to required rotational speed and requiredtorque. Meanwhile, when the rotary electric machine 3 functions as agenerator and is supplied with electric power from the side of therotary electric machine 3, the inverter device 1 converts the generatedthree-phase AC power into DC power and charges the battery 2 bycontrolling the respective switching elements 14.

2. Entire Structure of Inverter Device

Next, the entire structure of the inverter device 1 will be describedmainly with reference to FIGS. 3 and 4. The inverter device 1 includesan inverter module 6, a capacitor 31, and the control board 41. Theseare received in an inverter case 5 (hereinafter, simply referred to as a“case 5”) that is formed in a rectangular parallelepiped shape. Theinverter module 6 is a module on which the above-mentioned invertercircuit 7 is mounted, and is interposed between the battery 2 and therotary electric machine 3. The capacitor 31 is further interposedbetween the battery 2 and the inverter module 6.

The inverter module 6 includes the base plate 11, the plurality ofswitching elements 14 that are provided on the base plate 11, and aconnecting support 21 that supports the plurality of bus bars 23, asmain components.

The base plate 11 is a plate-like member serving as a base on which theswitching elements 14 are placed. The base plate 11 is made of a metalmaterial such as copper or aluminum. As shown in FIG. 3 and the like, aninsulating member 12 and element substrates 13 are stacked on the uppersurface (the surface corresponding to +Z direction side; similarlyhereinafter) of the base plate 11, that is, the surface (element placingsurface 11 a) of the base plate 11 on which the switching elements 14are placed, so as to be parallel or substantially parallel to eachother. This stacking direction corresponds with the Z direction.

The insulating member 12 is formed of a sheet-like member that has bothelectric insulation and thermal conductivity, and is formed of a sheetmember made of a resin in this embodiment. The element substrates 13 aremade of a conductive material (for example, a metal material such ascopper or aluminum), and are fixedly bonded to the base plate 11 withthe insulating member 12 interposed therebetween by thermocompressionbonding. The element substrate 13 also functions as a heat spreader. Asshown in FIG. 3, in this embodiment, one insulating member 12 isdisposed on the base plate 11 and six element substrates 13 are disposedon the insulating member 12. These six element substrates 13 aredisposed so as to be lined up in two lines in the X direction and linedup in three lines in the Y direction.

One switching element 14 and one diode element 15 are disposed on theupper surface of each of the element substrates 13. Accordingly, in thisembodiment, six switching elements 14 and six diode elements 15 areprovided on the element placing surface 11 a of the base plate 11 withthe insulating member 12 and the element substrates 13 interposedtherebetween. Further, the inverter circuit 7 includes the switchingelements 14 and the diode elements 15. In this embodiment, an IGBT(insulated gate bipolar transistor) is used as the switching element 14.Meanwhile, a MOSFET (metal oxide semiconductor field effect transistor)or the like may also be used as the switching element 14. Furthermore,in this embodiment, as shown in FIG. 3 or the like, the switchingelement 14 and the diode element 15, which are placed on the sameelement substrate 13, are disposed adjacent to each other so as to belined up in the X direction.

A first electrode member 17 is disposed while electrically connectingthe upper surface (emitter electrode) of the switching element 14 to theupper surface (anode electrode) of the diode element 15. In thisembodiment, the first electrode member 17 is formed by bending abelt-like member (plate-like member) that has a constant width. Further,a second electrode member 18 is placed on the upper surface of each ofthe element substrates 13. The second electrode member 18 electricallyconnects the lower surface (collector electrode) of the switchingelement 14 to the lower surface (cathode electrode) of the diode element15 through the element substrate 13. The second electrode member 18 isformed of a block-like member in this embodiment. Both the first andsecond electrode members 17 and 18 are made of a conductive material(for example, a metal material such as copper or aluminum).

In this embodiment, the switching elements (14 a and 14 d), (14 b and 14e), and (14 c and 14 f) making a pair, the respective correspondingdiode elements 15, the respective corresponding first electrode members17, the respective corresponding second electrode members 18, and therespective corresponding bus bars 23 a, 23 b, and 23 c (hereinafter,these may be simply referred to as the “diode elements 15, and thelike”) form the respective legs of the inverter circuit 7. Among these,the switching elements 14 a, 14 b, and 14 c, the respectivecorresponding diode elements 15, and the like form the respective upperstage arms of the inverter circuit 7. Further, the switching elements 14d, 14 e, and 14 f, the respective corresponding diode elements 15, andthe like form the respective lower stage arms of the inverter circuit 7.

Furthermore, in this embodiment, as shown in FIGS. 3 and 4, thedirection in which the upper and lower stage arms of each leg areconnected to each other is set to a direction along the X direction. Inthis embodiment, as being capable of being understood from FIG. 4, theranges, which are occupied by the upper and lower stage arms of therespective legs in the Y direction, are slightly deviated from eachother without exactly corresponding with each other. However, theseupper and lower stage arms occupy substantially the same range in the Ydirection, and a direction in which the upper and lower stage arms areconnected to each other is substantially along the X direction.Accordingly, the “direction along the X direction” of this embodimentrepresents a direction parallel to the X direction or a direction thatis inclined with respect to the X direction by a predetermined angle. Inthis case, the predetermined angle may be in the range of, for example,±20°, preferably, in the range of ±10°. Since the direction in which theupper and lower stage arms of each leg are connected to each other isset to the direction along the X direction as described above, it ispossible to simplify the shapes of the portions of the bus bars 23 a, 23b, and 23 c, which are toward the rotary electric machine-connectionterminals 25 a, 25 b, and 25 c, into the shape close to the shape of astraight line along the X direction. Further, since it is possible tomake the shapes of the bus bars 23 a, 23 b, and 23 c be the same as eachother or substantially same as each other, it is possible to simplifythe disposition of each of the bus bars 23 a, 23 b, and 23 c.

Furthermore, in this embodiment, the diode element 15 and the switchingelement 14 forming each aim are disposed adjacent to each other in the Xdirection. Moreover, the belt-like first electrode member 17, whichconnects the switching element 14 to the diode element 15, is alsodisposed so as to extend in the X direction accordingly. As describedabove, each of the arms is formed so as to extend in the X direction asa whole. In other words, the upper and lower stage arms of each legs aredisposed so that the longitudinal direction of each of the upper andlower stage arms is the direction along the X direction. Accordingly, itis possible to reduce the lengths of the bus bars 23 d and 23 e in the Ydirection as compared to the case where the upper and lower stage armsare disposed so that the longitudinal direction of each of the upper andlower stage arms is the direction along the Y direction. Therefore, itis possible to reduce the electrical resistance of the bus bars 23 d and23 e serving as the transmission path for DC power, so that it ispossible to improve energy efficiency.

Further, in this embodiment, three legs are sequentially arrayed in theY direction. In this embodiment, the ranges, which are occupied in the Xdirection by the upper stage arms forming the respective legs, exactlycorrespond with each other. Likewise, the ranges, which are occupied inthe X direction by the lower stage arms forming the respective legs,exactly correspond with each other. Accordingly, in this embodiment,three legs are sequentially arrayed in the direction parallel to the Ydirection. Therefore, it is possible to simplify the shapes of portionsof the bus bars 23 d and 23 e, which connect the respective legs, intothe shape close to the shape of a straight line along the Y direction.Furthermore, since it is possible to make the shapes of the bus bars 23d and 23 e be the same as each other or substantially the same as eachother, it is possible to simplify the disposition of each of the busbars 23 d and 23 e.

As shown in FIG. 3, heat dissipating fins 11 b are provided on the sideof the base plate 11 opposite to the element placing surface 11 a. Inthis embodiment, the heat dissipating fins 11 b are formed integrallywith the base plate 11. The heat dissipating fins 11 b dissipate theheat of the switching elements 14 (heat generated due to a switchingoperation), which is transferred to the base plate 11 through theelement substrates 13 and the insulating member 12, from the surfacethereof. As shown in FIGS. 3 and 6 and the like, in this embodiment, theheat dissipating fins 11 b are formed so as to be erected in the Zdirection and extend in the shape of a flat plate in the directionparallel to the Y direction.

The connecting support 21 is a structure that supports the plurality ofbus bars 23, and is provided on the side of the element placing surface11 a of the base plate 11 so as to be fixed to the base plate 11. Fivebus bars 23, that is, a first bus bar 23 a, a second bus bar 23 b, athird bus bar 23 c, a fourth bus bar 23 d, and a fifth bus bar 23 e areprovided as the bus bars 23 in this embodiment. These five bus bars 23are integrally supported by the connecting support 21. The bus bar 23 ismade of a conductive material (for example, a metal material such ascopper or aluminum), and is formed by bending a flat plate-like memberin a predetermined shape in this embodiment.

The first bus bar 23 a, the second bus bar 23 b, and the third bus bar23 e are electrical connection members that electrically connect theswitching elements 14 and the diode elements 15 of the upper stage armsto the rotary electric machine-connection terminals 25 through the firstelectrode members 17, respectively, and electrically connect theswitching elements 14 and the diode elements 15 of the lower stage armsto the rotary electric machine-connection terminals 25 through thesecond electrode members 18, respectively. The bus bars 23 a, 23 b, and23 c extend in a direction along the X direction as a whole so as to beparallel to the direction in which the upper and lower stage arms ofeach leg are connected to each other. The fourth bus bar 23 d is anelectrical connection member that electrically connects the diodeelements 15 and the switching elements 14 of the upper stage arms to apositive electrode-side DC terminal 34 a, that is, a DC terminal 34corresponding to the positive electrode P through the second electrodemembers 18. The fifth bus bar 23 e is an electrical connection memberthat electrically connects the diode elements 15 and the switchingelements 14 of the lower stage arms to a negative electrode-side DCterminal 34 b, that is, a DC terminal 34 corresponding to the negativeelectrode N through the first electrode members 17. The bus bars 23 dand 23 e extend in a direction along the Y direction as a whole so as tobe parallel to each other between a set of three upper stage arms and aset of three lower stage arms.

In this embodiment, a plurality of joint portions 24, which aresupported by the connecting support 21 formed integrally with therespective bus bars 23, are joined to the upper surfaces of the firstand second electrode members 17 and 18 so as to be pressed against theupper surfaces of the first and second electrode members 17 and 18, sothat the electrical connection between the respective bus bars 23 andthe first and second electrode members 17 and 18 is achieved. In theembodiment, the respective bus bars 23 are joined to the first andsecond electrode members 17 and 18 by laser welding that uses a YAGlaser, a CO₂ laser, a semiconductor laser, or the like.

The rotary electric machine-connection terminals 25 are terminals thatinput and output AC power to and from the rotary electric machine 3 as adriving powersource of the vehicle V. In this embodiment, the rotaryelectric machine-connection terminals 25 a, 25 b, and 25 c for threephases are provided as the rotary electric machine-connection terminals25. In this embodiment, the rotary electric machine-connection terminal25 a for a U phase is formed integrally with the first bus bar 23 a atthe end portion of the first bus bar 23 a corresponding to +X directionside. Likewise, the rotary electric machine-connection terminal 25 b fora V phase is formed integrally with the second bus bar 23 b at the endportion of the second bus bar 23 b corresponding to +X direction side,and the rotary electric machine-connection terminal 25 c for a W phaseis formed integrally with the third bus bar 23 c at the end portion ofthe third bus bar 23 c corresponding to +X direction side. These threerotary electric machine-connection terminals 25 a, 25 b, and 25 c aresequentially arrayed in the direction parallel to the Y direction inaccordance with the array of the three legs forming the inverter circuit7. Meanwhile, in this embodiment, as described below, the Y directioncorresponds with a direction that is perpendicular to a rotating shaft 3a of the rotary electric machine 3. Accordingly, the three rotaryelectric machine-connection terminals 25 a, 25 b, and 25 c aresequentially arrayed in a direction perpendicular to the rotating shaft3 a. In this embodiment, the rotary electric machine-connectionterminals 25 a, 25 b, and 25 c for the respective phases correspond to“AC phase-terminals” of the invention.

The capacitor 31 is provided in parallel between the battery 2 and theinverter module 6, and smoothes DC power between the battery 2 and theinverter module 6. The capacitor 31 includes a case portion 31 a and acapacitor element 31 b. The case portion 31 a is formed in the shape ofa bathtub that is formed so as to cover both sides in the X direction,both sides in the Y direction, and one side in the Z direction and has arectangular shape when seen in the Z direction (in plan view seen in theZ direction; hereinafter similarly, even in the views when seen in therespective directions). Power supply terminals 33 that input and outputDC power to and from the battery 2 and DC terminals 34 that input andoutput DC power to and from the switching elements 14 are formedintegrally with the case portion 31 a. The power supply terminals 33 andthe DC terminals 34 are electrically connected to each other bycapacitor bus bars 36. The capacitor bus bars 36 are made of aconductive material (for example, a metal material such as copper oraluminum), and are formed in the shape of a flat plate in thisembodiment. Two capacitor bus bars 36, that is, first and secondcapacitor bus bars 36 a and 36 b are provided as the capacitor bus bars36 in this embodiment. In this embodiment, the capacitor bus bars 36 aand 36 b correspond to “capacitor connecting members” of the invention.

The first capacitor bus bar 36 a electrically connects a positiveelectrode-side power supply terminal 33 a, which is a power supplyterminal 33 corresponding to the positive electrode P, to the positiveelectrode-side DC terminal 34 a (see FIG. 2). The second capacitor busbar 36 b electrically connects a negative electrode-side power supplyterminal 33 b, which is a power supply terminal 33 corresponding to thenegative electrode N, to the negative electrode-side DC terminal 34 b.As shown in FIG. 4, the first and second capacitor bus bars 36 a and 36b are disposed at positions that overlap each other when seen in the Zdirection. Further, in the case portion 31 a formed in the shape of abathtub, a terminal of one electrode of the capacitor element 31 b isconnected to the first capacitor bus bar 36 a and a terminal of theother electrode of the capacitor element 31 b is connected to the secondcapacitor bus bar 36 b.

Each of the first and second capacitor bus bars 36 a and 36 b is formedin a rectangular shape as a whole when seen in the Z direction.Furthermore, the first and second capacitor bus bars 36 a and 36 binclude protruding portions 37 that protrude in −X direction and have arectangular shape when seen in the Z direction. The two protrudingportions 37 are formed at the end portions of the capacitor bus bars 36a and 36 b corresponding to −X direction side at positions that aredifferent from each other in the Y direction. A resistor 38 is connectedbetween these two protruding portions 37. The resistor 38, which isconnected in parallel to the capacitor element 31 b, functions as adischarge resistor that discharges charges accumulated in the capacitorelement 31 b when the supply of electric power from the battery 2 isstopped.

Branch connection portions 39, which are branched from the protrudingportions 37 and extend toward +Z direction side in the Z direction, areformed at the end portions of the protruding portions 37 of the firstand second capacitor bus bars 36 a and 36 b, which correspond to −Xdirection side, respectively. The branch connection portions 39 are madeof a conductive material (for example, a metal material such as copperor aluminum), and are formed in a linear shape (the shape of a wire) inthis embodiment. The capacitor element 31 b, the first and secondcapacitor bus bars 36 a and 36 b, the resistor 38, and a part of thebranch connection portions 39 corresponding to −Z direction side aremolded with a resin while being disposed in the case portion 31 a.Meanwhile, an epoxy resin, an acrylic resin, a urethane resin, and thelike may be used as a mold resin. A part of the branch connectionportions 39 corresponding to +Z direction side are exposed from theresin and extend in the Z direction.

The control board 41 mainly has a function of controlling the operationsof the respective switching elements 14. For this reason, the controlboard 41 is provided with a drive circuit 43 that individually controlsthe switching of at least the switching elements 14 (see FIG. 5).Further, in this embodiment, the control board 41 is also provided witha voltage detecting circuit 44 that detects the voltage between bothelectrodes of the capacitor 31. Furthermore, the control board 41 isalso provided with a current detecting circuit that detects alternatingcurrent flowing through the bus bars 23 a, 23 b, and 23 c; a temperaturedetecting circuit that detects the temperatures of the switchingelements 14; and the like. In this embodiment, the control board 41 isdisposed on the upper side of the inverter module 6 and the capacitor 31(+Z direction side) so as to be close to the inverter module 6 and thecapacitor 31.

3. Configuration of Respective Components of Inverter Device

Next, the configuration of the respective components of the inverterdevice 1 will be described mainly with reference to FIGS. 4 to 7. Here,the configuration seen in the Z direction, the configuration seen in theX direction, and the configuration between two terminals 33 and 34 willbe sequentially described.

3-1. Configuration Seen in Z Direction

In this embodiment, the connecting support 21, which support theplurality of (five in this embodiment) bus bars 23, is provided so as tobe fixed to the base plate 11. Here, among the five bus bars 23, the busbars 23 a, 23 b, and 23 c extend in the direction along the X directionas a whole. The bus bars 23 d and 23 e extend in the direction along theY direction as a whole between the upper and lower arms, here, at theposition of the center 11 c of gravity (see FIG. 7) of the base plate 11in the X direction (the disposition position in the X direction;similarly hereinafter) when seen in the Z direction. The bus bars 23 a,23 b, and 23 c are perpendicular to the bus bars 23 d and 23 e when seenin the Z direction, respectively.

The bus bars 23 a, 23 h, and 23 c are formed so that the length of eachof the portions of the bus bars 23 a, 23 b, and 23 c in the X directionon +X direction side of the bus bars 23 d and 23 e (the length in the Xdirection; similarly hereinafter) is longer than that of each of theportions of the bus bars 23 a, 23 b, and 23 c in the X direction on −Xdirection side of the bus bars 23 d and 23 e. For this reason, each ofthe bus bars 23 a, 23 b, and 23 c is disposed so as to protrude from thebase plate 11 in the X direction. In this embodiment, the bus bars 23 a,23 b, and 23 c are disposed so as to protrude from the base plate 11toward +X direction side. Meanwhile, the end portions of the bus bars 23a, 23 b, and 23 c corresponding to −X direction side are disposed at thepositions that overlap the base plate 11 when seen in the Z direction.

Further, the rotary electric machine-connection terminals 25 (25 a, 25b, and 25 c) for the respective phases are formed at the end portions ofthe bus bars 23 a, 23 b, and 23 c corresponding to +X direction side,respectively. Accordingly, in this embodiment, the rotary electricmachine-connection terminals 25 for the respective phases are disposedso as to protrude from the base plate 11 toward +X direction side.Furthermore, the rotary electric machine-connection terminals 25 aredisposed so as to also protrude from the connecting support 21 toward +Xdirection side. In this case, the rotary electric machine-connectionterminals 25 a, 25 b, and 25 c for the respective phases are disposed sothat the end portions of the rotary electric machine-connectionterminals corresponding to +X direction side are aligned with eachother. In this embodiment, a “base disposition area R2” is defined as anarea in which the base plate 11, the connecting support 21, the bus bars23 a, 23 b, and 23 c, and the rotary electric machine-connectionterminals 25 are disposed. As shown in FIG. 4, the base disposition areaR2 is a rectangular area that occupies an area from the end portion ofthe base plate 11 corresponding to −X direction side to the end portionsof the rotary electric machine-connection terminals 25 corresponding to+X direction side and occupies an area from the end portion of the baseplate 11 corresponding to −Y direction side to the end portion of theconnecting support 21 corresponding to +Y direction side, when seen inthe Z direction. Moreover, in this embodiment, the base disposition areaR2 is set so that long sides of the rectangular shape are parallel tothe X direction when seen in the Z direction.

Further, in this embodiment, a “capacitor disposition area R1” isdefined as an area in which the capacitor 31, and the power supplyterminals 33, the DC terminals 34, and the capacitor bus bars 36attached to the capacitor 31 are disposed. In this embodiment, all ofthe power supply terminals 33, the DC terminals 34, and the capacitorbus bars 36 are formed integrally with the case portion 31 a of thecapacitor 31 or are disposed in the case portion 31 a. Accordingly, thecapacitor disposition area R1 is set to a rectangular area correspondingto the shape of the case portion 31 a when seen in the Z direction.Furthermore, in this embodiment, the capacitor disposition area R1 isset so that long sides of the rectangular shape are parallel to the Xdirection when seen in the Z direction.

As shown in FIG. 4, the capacitor disposition area R1 and the basedisposition area R2 are disposed adjacent to each other in the Ydirection. Here, the capacitor disposition area R1 is set adjacent tothe base disposition area R2 on +Y direction side. In this case, thelength of the capacitor disposition area R1 in the X direction is set soas to be longer than the length of the base plate 11 in the X direction.In this embodiment, the position of the end portion of the case portion31 a, which corresponds to −X direction side and defines the end portionof the capacitor disposition area R1 corresponding to −X direction side,in the X direction and the position of the end portion of the base plate11, which corresponds to −X direction side, in the X direction areslightly deviated from each other without exactly corresponding witheach other. However, these positions are substantially the same as eachother. Meanwhile, the end portion of the case portion 31 a, whichcorresponds to +X direction side and defines the end portion of thecapacitor disposition area R1 corresponding to +X direction side, ispositioned at a position that is deviated from the end portion of thebase plate 11, which corresponds to +X direction side, toward +Xdirection side.

In this configuration, an area, which does not overlap the base plate 11and overlaps the capacitor disposition area R1 when seen in the Ydirection, is formed at the position adjacent to the base plate 11 on +Xdirection side due to the difference between the length of the capacitordisposition area R1 and the length of the base plate 11 in the Xdirection. In this embodiment, the rotary electric machine-connectionterminals 25 are disposed so that the entire rotary electricmachine-connection terminals are received in the area formed in thisway, that is, the area between the end portion of the base plate 11corresponding to +X direction side and the end portion of the caseportion 31 a corresponding to +X direction side in the X direction.

Furthermore, in this embodiment, the length and position of thecapacitor disposition area R1 in the X direction are set so as tocorrespond with the length and position of the base disposition area R2in the X direction. Here, both the length and position of the capacitordisposition area R1 in the X direction are set so as to correspond withboth the length and position of the base disposition area R2 in the Xdirection.

In this embodiment, the position of the end portion of the base plate11, which corresponds to −X direction side and defines the end portionof the base disposition area R2 corresponding to −X direction side, inthe X direction and the position of the end portion of the case portion31 a, which corresponds to −X direction side and defines the end portionof the capacitor disposition area R1 corresponding to −X direction side,in the X direction are slightly deviated from each other without exactlycorresponding with each other. However, these positions aresubstantially the same as each other. Likewise, the positions of the endportions of the rotary electric machine-connection terminals 25, whichcorrespond to +X direction side and define the end portion of the basedisposition area R2 corresponding to +X direction side, in the Xdirection and the position of the end portion of the case portion 31 a,which corresponds to +X direction side and defines the end portion ofthe capacitor disposition area R1 corresponding to +X direction side, inthe X direction are slightly deviated from each other without exactlycorresponding with each other. However, these positions aresubstantially the same as each other. Accordingly, in this embodiment,the positions of both end portions of the capacitor disposition area R1in the X direction are set so as to be substantially the same as thepositions of both end portions of the base disposition area R2 in the Xdirection, respectively. Naturally, the length of the capacitordisposition area R1 in the X direction is substantially equal to thelength of the base disposition area R2 in the X direction.

As described above, “correspond” of this embodiment means that events,that is, objects to be compared (here, the events include the positionin the X direction and the length in the X direction) are substantiallythe same as each other. That is, “correspond” includes not only a statewhere events, that is, objects to be compared are exactly the same aseach other but also a state where there are differences between theseevents. For example, “correspond” also includes a state wheredifferences between the events, that is, the objects to be compared aresufficiently small as compared to all of the events and the events aresubstantially the same as each other so that peripheral portions can bedesigned or manufactured, or a state where there are differences causedby allowable errors in design or manufacture. An “allowable difference”in this case may be within ±10%, preferably, within ±5%, and morepreferably, within ±3% on the basis (100%) of, for example, the lengthof each of the areas R1 and R2 in the X direction.

Meanwhile, the capacitor 31 has a relatively large degree of freedom inthe design of the size and shape thereof, as compared to the rotaryelectric machine-connection terminals 25 that input and output AC powerto and from the rotary electric machine 3 or the base plate 11 on whichthe switching elements 14 are provided. For this reason, it isrelatively easy to adjust the size and shape of the capacitor 31 inaccordance with the size and shape of the capacitor disposition area R1.In consideration of this, in this embodiment, the length and position ofthe capacitor disposition area R1 in the X direction are set so as tocorrespond with the length and position of the base disposition area R2in the X direction. Accordingly, in terms of a positional relationshipin the direction along the X direction, the capacitor 31 can be disposedso as to be received in the area that is occupied by all of the baseplate 11 and the rotary electric machine-connection terminals 25.Therefore, all of the base plate 11, the rotary electricmachine-connection terminals 25, and the capacitor 31 can be disposed soas to be compactly received in the case 5, which has a rectangular shapewhen seen in the Z direction, without dead spaces. As a result, it ispossible to reduce the size of the inverter device 1.

Further, in this embodiment, as shown in FIG. 4, the control board 41 isdisposed so that the end portion of the control board corresponding to−X direction side is aligned with both the capacitor disposition area R1and the base disposition area R2 of which the end portions correspondingto −X direction side substantially correspond with each other.Accordingly, in this embodiment, the positions of the end portions ofthe capacitor disposition area R1, the base disposition area R2, and thecontrol board 41, which correspond to −X direction side when seen in theZ direction, in the X direction are substantially the same as eachother. Furthermore, the control board 41 is disposed so that the endportion of the control board corresponding to +X direction side isaligned with the end portion of the base plate 11 corresponding to +Xdirection side. Accordingly, in this embodiment, the positions of theend portions of the base plate 11 and the control board 41, whichcorrespond to +X direction side when seen in the Z direction, in the Xdirection are substantially the same as each other. Therefore, thecontrol board 41, which is formed in a rectangular shape in accordancewith the shape of the case 5, is disposed at a position that overlapsboth the capacitor disposition area R1 and the base disposition area R2when seen in the Z direction. More specifically, the control board 41 isdisposed at a position that partially overlaps a part of the capacitordisposition area R1 corresponding to −X direction side and overlaps allof the area of the base disposition area R2 in which the base plate 11is disposed, when seen in the Z direction.

Meanwhile, the control board 41 is disposed at a position that does notoverlap the rotary electric machine-connection terminals 25 (a positiondifferent from the positions of the rotary electric machine-connectionterminals 25) when seen in the Z direction. Accordingly, it is possibleto allow the rotary electric machine-connection terminals 25 to beelectrically connected to the coils 3 b of the rotary electric machine 3without interference with the control board 41, while all of the maincomponents, which also include the control board 41, of the inverterdevice 1 are received in the case 5 that has a rectangular shape whenseen in the Z direction.

3-2. Configuration Seen in X Direction

In this embodiment, the base plate 11 includes the heat dissipating fins11 b that are erected in the Z direction and provided on the surface ofthe base plate 11 opposite to the element placing surface 11 a (seeFIGS. 3 and 5, and the like). For this reason, a disposition area forthe heat dissipating fins 11 b is also included in the “base dispositionarea R2” that is defined as the area in which the base plate 11, theconnecting support 21, the bus bars 23 a, 23 b, and 23 c, and the rotaryelectric machine-connection terminals 25 are disposed. In this case, asshown in FIG. 5, the base disposition area R2 is a rectangular area thatoccupies an area from tip portions of the heat dissipating fins 11 b(the end portions of the heat dissipating fins corresponding to −Zdirection side) to the end portion of the connecting support 21corresponding to +Z direction side and occupies an area from the endportion of the base plate 11 corresponding to −Y direction side to theend portion of the connecting support 21 corresponding to +Y directionside, when seen in the X direction. Meanwhile, the capacitor dispositionarea R1 is set to a rectangular area corresponding to the shape of thecase portion 31 a even when seen in the X direction.

In this case, as shown in FIG. 5, the length and position of thecapacitor disposition area R1 in the Z direction are set so as tocorrespond with the length and position of the base disposition area R2in the Z direction. Here, both the length and position of the capacitordisposition area R1 in the Z direction are set so as to correspond withboth the length and position of the base disposition area R2 in the Zdirection.

In this embodiment, the positions of the tip portions of the heatdissipating fins 11 b (the end portions of the heat dissipating finscorresponding to −Z direction side), which define the end portion of thebase disposition area R2 corresponding to −Z direction side, in the Zdirection and the position of the bottom of the case portion 31 a (theend portion of the case portion corresponding to −Z direction side),which defines the end portion of the capacitor disposition area R1corresponding to −Z direction side, in the Z direction are slightlydeviated from each other without exactly corresponding with each other.However, these positions are substantially the same as each other.Likewise, the position of the end portion of the connecting support 21corresponding to +Z direction side, which defines the end portion of thebase disposition area R2 corresponding to +Z direction side, in the Zdirection and the position of the end portion of the mold resincorresponding to +Z direction side (not shown), which defines the endportion of the capacitor disposition area R1 corresponding to +Zdirection side, in the Z direction are slightly deviated from each otherwithout exactly corresponding with each other. However, these positionsare substantially the same as each other. Accordingly, in thisembodiment, the positions of both end portions of the capacitordisposition area R1 in the Z direction are set so as to be substantiallythe same as the positions of both end portions of the base dispositionarea R2 in the Z direction, respectively. Naturally, the length of thecapacitor disposition area R1 in the Z direction is substantially equalto the length of the base disposition area R2 in the Z direction.

As described above, in this embodiment, the length and position of thecapacitor disposition area R1 in the Z direction are set so as tocorrespond with the length and position of the base disposition area R2in the Z direction. Accordingly, in terms of a positional relationshipin the direction along the Z direction, the capacitor 31 can be disposedso as to be received in the area that is occupied by all of the baseplate 11 including the heat dissipating fins 11 b, the rotary electricmachine-connection terminals 25, and the connecting support 21.Therefore, all of the base plate 11 including the heat dissipating fins11 b, the rotary electric machine-connection terminals 25, theconnecting support 21, and the capacitor 31 can be disposed so as to becompactly received in the case 5, which has a rectangular shape whenseen in the X direction, without dead spaces.

As described above, in this embodiment, the length and position of thecapacitor disposition area R1 are set so as to correspond with thelength and position of the base disposition area R2 in both the Xdirection and the Z direction. For this reason, all of the maincomponents of the inverter device 1 can be compactly received in thecase 5, which has a rectangular parallelepiped shape, without deadspaces. Accordingly, it is possible to reduce the size of the inverterdevice 1. There are many cases where there is a limitation on themounting of the inverter device on the vehicle V in the use for thecontrol of the rotary electric machine 3 provided in the hybrid vehicleV as in this embodiment. For this reason, the structure of the inverterdevice 1 of which the size can be reduced as much as possible asdescribed above has a significant merit particularly in theabove-mentioned use.

Moreover, in this embodiment, as shown in FIG. 5, the control board 41is disposed adjacent to both the capacitor disposition area R1 and thebase disposition area R2, of which the end portions corresponding to +Zdirection side substantially correspond with each other, in the +Zdirection. Accordingly, the increase of the size of the inverter device1 in the Z direction is suppressed. In this case, in this embodiment,the drive circuit 43 provided on the control board 41 is disposedadjacent to the base disposition area R2 in the +Z direction and thevoltage detecting circuit 44 provided on the control board 41 isdisposed adjacent to the capacitor disposition area R1 in the +Zdirection. Further, while passing through the control board 41, thebranch connection portions 39, which are formed at the protrudingportions 37 of the capacitor bus bars 36 a and 36 b and extend toward +Zdirection side in the shape of a straight line along the Z direction,are connected to the voltage detecting circuit 44 that is providedadjacent to the capacitor disposition area R1 in the +Z direction.Accordingly, it is possible to connect two capacitor bus bars 36 a and36 b, which are connected to both electrodes of the capacitor 31, to thevoltage detecting circuit 44 at the shortest distance.

3-3. Configuration of Power Supply Terminals and DC Terminals

Next, the configuration of the power supply terminals 33 and the DCterminals 34 will be described mainly with reference to FIG. 7. In thisembodiment, as described above, the rotary electric machine-connectionterminals 25 for the respective phases are disposed so as to protrudefrom the base plate 11 toward +X direction side and the length andposition of the capacitor disposition area R1 in the X direction are setso as to correspond with the length and position of the base dispositionarea R2 in the X direction. For this reason, when the lengths of thebase plate 11 and the capacitor 31 (the capacitor disposition area R1)in the X direction are compared with each other, the length of thecapacitor 31 in the X direction is longer. Accordingly, the position ofthe center 11 c of gravity of the base plate 11 in the X direction whenseen in the Z direction (the center of gravity of the planar shape ofthe base plate when seen in the Z direction; similarly hereinafter) isdifferent from the position of the center 31 c of gravity of thecapacitor 31 (which is regarded to substantially correspond with thecenter of gravity of the capacitor disposition area R1) in the Xdirection. In this embodiment, the center 31 c of gravity of thecapacitor 31 is disposed so as to be deviated from the center 11 c ofgravity of the base plate 11 toward +X direction side that is one sidein the X direction. Meanwhile, since each of the base plate 11 and thecapacitor 31 has a rectangular shape when seen in the Z direction, thecenters 11 c and 31 c of gravity of the base plate and the capacitor areintersections between virtual diagonal lines of the respective outeredges of the rectangular shapes of the base plate and capacitor whenseen in the Z direction.

Here, in this embodiment, as shown in FIG. 7, the DC terminals 34 aredisposed at the position of the center 11 c of gravity of the base plate11 in the X direction in accordance with the positions of the bus bars23 d and 23 e in the X direction. The reason for this is that it ispossible to make the shapes of the bus bars 23 d and 23 e, which connectthe DC terminals 34 to the respective switching elements 14, be the sameas each other or substantially the same as each other in this case. Forthis reason, in this embodiment, the position of the center 31 c ofgravity of the capacitor 31 in the X direction is disposed so as to bedeviated from the DC terminals 34 toward +X direction side.

In this structure, in this embodiment, the power supply terminals 33 andthe DC terminals 34 are disposed at the positions that arepoint-symmetrical to each other with respect to the center 31 c ofgravity of the capacitor 31 when seen in the Z direction. That is, thepower supply terminals 33 are disposed at the positions that arepoint-symmetrical to the DC terminals 34 with respect to the center 31 cof gravity of the capacitor 31 as a reference point. That is, the powersupply terminals 33 are disposed at any positions on the peripheral edgeportion of the case portion 31 a of the capacitor 31 and at thepositions on a virtual plane passing through the DC terminals 34 and thecenter 31 c of gravity of the capacitor 31. In this case, an offsetdistance from the DC terminal 34 to the center 31 c of gravity of thecapacitor 31 in the X direction (the length in the X direction) issubstantially equal to an offset distance from the center 31 c ofgravity of the capacitor 31 to the power supply terminal 33. Meanwhile,in this case, the power supply terminals 33 and the DC terminals 34 arenaturally disposed at positions that are different in the X direction.

Since the above-mentioned configuration of the power supply terminals 33and the DC terminals 34 has been employed in this embodiment, it ispossible to make the lengths of electrical connection paths, which passthrough the capacitor bus bars 36 a and 36 b and the respectivecapacitor elements 31 b provided between the power supply terminals 33and the DC terminals 34, be substantially equal to each other in thestructure where a plurality of (two in this embodiment) capacitorelements 31 b are connected in parallel between the power supplyterminals 33 and the DC terminals 34. This is schematically shown inFIG. 7. Accordingly, it is possible to substantially equalize thecurrents that flow through the respective capacitor elements 31 b.Further, since the amount of heat generated by the respective capacitorelements 31 b is also substantially equalized due to this, it ispossible to reduce the size of each of the capacitor elements 31 b andthus to reduce the entire size of the inverter device 1 and thecapacitor 31.

4. Configuration in State where Inverter Device is Mounted on Vehicle

As apparent from the description having been made until now, theextending direction of the flat plate-like heat dissipating fins 11 bprovided on the base plate 11 has been the direction along the Ydirection in this embodiment. Further, the capacitor 31 is disposedadjacent to the base plate 11, which includes the heat dissipating fins11 b, on +Y direction side. Furthermore, the power supply terminals 33are formed integrally with a wall portion, which corresponds to +Ydirection side, of the case portion 31 a of the capacitor 31. Moreover,the three rotary electric machine-connection terminals 25 a, 25 b, and25 c are sequentially arrayed in the direction parallel to the Ydirection.

Meanwhile, the vehicle drive device 62 according to this embodiment ismounted on a FF (Front Engine Front Drive) type hybrid vehicle V asshown in FIG. 8, and is disposed adjacent to an internal combustionengine 61, which is transversely mounted in a driving power sourcereceiving chamber (engine room) provided on the front side of a driver'sseat, so as to be lined up in the width direction of the vehicle V. Therotating shaft 3 a of the rotary electric machine 3, which is includedin the vehicle drive device 62, is disposed parallel to a crankshaft ofthe internal combustion engine 61, and is connected to the crankshaft soas to be driven. That is, the crankshaft of the internal combustionengine 61 and the rotating shaft 3 a of the rotary electric machine 3are disposed in the width direction of the vehicle V, and are disposedperpendicular to the travel direction T of the vehicle V.

In this structure, the inverter device 1 according to this embodiment isfixed to the upper portion of the vehicle drive device 62 and mounted onthe vehicle V in the following state. Here, the X direction, which hasbeen described until now, corresponds with the width direction of thevehicle V, that is, a direction parallel to the rotating shaft 3 a ofthe rotary electric machine 3. Further, the Y direction corresponds withthe travel direction T of the vehicle V, that is, a directionperpendicular to the rotating shaft 3 a of the rotary electric machine3. Meanwhile, in this embodiment, −Y direction side corresponds with thefront side in the travel direction T of the vehicle V and +Y directionside corresponds with the rear side in the travel direction T of thevehicle V. The Z direction may be slightly inclined with respect to thetravel direction T of the vehicle V, but corresponds with asubstantially vertical direction (see FIG. 1).

Accordingly, in the state where the inverter device is mounted on thevehicle V in this embodiment, the extending direction of the flatplate-like heat dissipating fins 11 b provided on the base plate 11 ofthe inverter device 1 is a direction along the travel direction T of thevehicle V and the capacitor 31 is disposed adjacent to the heatdissipating fins 11 b on the rear side in the travel direction T of thevehicle V. Therefore, travel wind, which is generated due to the forwardtravel of the vehicle V, is appropriately guided to the spaces betweenthe plurality of heat dissipating fins 11 b, so that it is possible toefficiently dissipate heat from the heat dissipating fins 11 b. As aresult, it is possible to efficiently cool the switching elements 14.Further, since the travel wind flowing between the heat dissipating fins11 b is appropriately guided to the capacitor 31, it is also possible toefficiently cool the capacitor 31.

Here, the heat dissipating fins 11 b provided on the base plate 11 areprovided on the side opposite to the vehicle drive device 62 and therotary electric machine 3 with respect to the element placing surface 11a, here, on the upper side of the base plate in the vertical direction.Accordingly, the heat dissipating fins 11 b are disposed at the positiondistant from the vehicle drive device 62 and the rotary electric machine3 which generate a relatively large amount of heat. Therefore, since theheat dissipating fins are not easily affected by the heat generated bythe rotary electric machine 3 and cooling air is easily supplied to theheat dissipating fins 11 b, heat is efficiently dissipated from the baseplate 11 by the heat dissipating fins 11 b. As a result, it is possibleto efficiently cool the switching elements 14.

Further, the power supply terminals 33 are disposed on the rear side ofthe capacitor 31 or the inverter module 6 (see FIGS. 3 and 4, and thelike), which includes the three rotary electric machine-connectionterminals 25 a, 25 b, and 25 c, in the travel direction T of the vehicleV. In this embodiment, as shown in FIG. 8, the power supply terminals 33are disposed at the position of the rearmost end portion of the case 5in the travel direction T of the vehicle V. The battery 2 is connectedto the power supply terminals 33 through electric power lines or thelike.

Here, there are many cases where the battery 2, which tends to berelatively large, is generally mounted on the vehicle on the rear sideof the driving power source receiving chamber (engine room), such asbelow seats of the vehicle V, in a center tunnel, in a trunk room, orthe like as shown even in FIG. 8. In this respect, in theabove-mentioned structure, the power supply terminals 33 are provided atthe position of the rearmost end portion of the case in the traveldirection T of the vehicle V. Accordingly, it is possible toelectrically connect the power supply terminals 33 to the battery 2 withthe shortest path. Therefore, it is possible to simplify the electricalconnection structure between the inverter device 1 and the battery 2.

Moreover, in the state where the inverter device is mounted on thevehicle V in this embodiment, the three rotary electricmachine-connection terminals 25 a, 25 b, and 25 c are disposed on thesame side of the base plate 11 in the width direction of the vehicle.Further, the three rotary electric machine-connection terminals 25 a, 25b, and 25 c are sequentially arrayed in the travel direction T of thevehicle V, that is, in the direction perpendicular to the rotating shaft3 a of the rotary electric machine 3. Furthermore, in this embodiment,the rotary electric machine-connection terminals 25 a, 25 b, and 25 care disposed so as to overlap the coils 3 b of the rotary electricmachine 3 (here, particularly, coil end portions that are portionsprotruding in an axial direction from stators of the rotary electricmachine 3) when seen in a radial direction of the rotary electricmachine 3. In this embodiment, the rotary electric machine-connectionterminals 25 a, 25 b, and 25 c are disposed on the upper side of thevehicle drive device 62, which includes the rotary electric machine 3,in the vertical direction so as to overlap the coils 3 b of the rotaryelectric machine 3 in plan view seen in the vertical direction.Accordingly, it is possible to connect the rotary electricmachine-connection terminals 25 a, 25 b, and 25 c to the coils 3 b ofthe rotary electric machine 3 along the radial direction of the rotaryelectric machine 3 in the shape of a straight line on the same side inthe axial direction of the rotary electric machine 3. Therefore, it ispossible to electrically connect the rotary electric machine-connectionterminals 25 a, 25 b, and 25 c to the coils 3 b by a minimum number ofnecessary members, so that it is possible to simplify the electricalconnection structure between the inverter device 1 and the coils 3 b.

As described above, in the inverter device 1 according to thisembodiment, the disposition positions of the respective components ofthe inverter device 1 are optimized in consideration of the state wherethe inverter device is mounted on the vehicle V. Accordingly, it ispossible to simplify both the electrical connection structure betweenthe inverter device 1 and the rotary electric machine 3 and theelectrical connection structure between the inverter device 1 and thebattery 2, and to secure the performance for cooling the switchingelements 14, the capacitor 31, or the like.

5. Other Embodiments

Finally, other embodiments of the inverter device according to theinvention will be described. Meanwhile, as long as there is noinconsistency, structures disclosed in the following respectiveembodiments may be combined with structures disclosed in otherembodiments in order to be applied.

(1) A case where the length and position of the capacitor dispositionarea R1 in the X direction are set so as to correspond with the lengthand position of the base disposition area R2 in the X direction has beendescribed by way of example in the above-mentioned embodiment. However,the embodiment of the invention is not limited thereto. That is, forexample, a structure where the lengths of the capacitor disposition areaR1 and the base disposition area R2 in the X direction are set so as notto correspond with each other is also one preferred embodiment of theinvention. In this case, a structure where the position of only one ofboth end portions of the capacitor disposition area R1 in the Xdirection is set so as to correspond with the position of only one ofboth end portions of the base disposition area R2 in the X direction, ora structure where the positions of both end portions of the capacitordisposition area R1 in the X direction are set so as not to correspondwith the positions of both end portions of the base disposition area R2in the X direction may be employed. Alternatively, a structure where thelengths of the capacitor disposition area R1 and the base dispositionarea R2 in the X direction are set so as to correspond with each otherand the positions of both end portions of the capacitor disposition areaR1 in the X direction are set so as not to correspond with the positionsof both end portions of the base disposition area R2 in the X directionis also one preferred embodiment of the invention.

(2) A case where the length and position of the capacitor dispositionarea R1 in the Z direction are set so as to correspond with the lengthand position of the base disposition area R2 in the Z direction has beendescribed by way of example in the above-mentioned embodiment. However,the embodiment of the invention is not limited thereto. That is, forexample, a structure where the lengths of the capacitor disposition areaR1 and the base disposition area R2 in the Z direction are set so as notto correspond with each other is also one preferred embodiment of theinvention. In this case, a structure where the position of only one ofboth end portions of the capacitor disposition area R1 in the Zdirection is set so as to correspond with the position of only one ofboth end portions of the base disposition area R2 in the Z direction, ora structure where the positions of both end portions of the capacitordisposition area R1 in the Z direction are set so as not to correspondwith the positions of both end portions of the base disposition area R2in the Z direction may be employed. Alternatively, a structure where thelengths of the capacitor disposition area R1 and the base dispositionarea R2 in the Z direction are set so as to correspond with each otherand the positions of both end portions of the capacitor disposition areaR1 in the Z direction are set so as not to correspond with the positionsof both end portions of the base disposition area R2 in the Z directionis also one preferred embodiment of the invention.

(3) A case where the control board 41 is disposed adjacent to both thecapacitor disposition area R1 and the base disposition area R2 in the Zdirection has been described by way of example in the above-mentionedembodiment. However, the embodiment of the invention is not limitedthereto. That is, for example, a structure where the control board 41 isdisposed so as to be distant from the capacitor disposition area R1 andthe base disposition area R2 in the Z direction to some extent is alsoone preferred embodiment of the invention.

(4) A case where the branch connection portions 39 branched andextending from the capacitor bus bars 36 a and 36 b are connected to thevoltage detecting circuit 44 while passing through the control board 41has been described by way of example in the above-mentioned embodiment.However, the embodiment of the invention is not limited thereto. Thatis, a structure where the branch connection portions 39 go around thecontrol board 41 and are connected to the voltage detecting circuit 44without passing through the control board 41 is also one preferredembodiment of the invention.

(5) A case where the power supply terminals 33 are disposed at thepositions point-symmetrical to the DC terminals 34 with respect to thecenter 31 c of gravity of the capacitor 31 as a reference point and aredisposed on the rear side of the rotary electric machine-connectionterminals 25 a, 25 b, and 25 c or the capacitor 31 in the traveldirection T of the vehicle V has been described by way of example in theabove-mentioned embodiment. However, the embodiment of the invention isnot limited thereto. That is, the disposition positions of the powersupply terminals 33 may be arbitrarily set regardless of the dispositionpositions of the DC terminals 34 or the center 31 c of gravity of thecapacitor 31. Further, a structure where the power supply terminals 33are disposed at the same positions as or on the front side of at leastone of the rotary electric machine-connection terminals 25 a, 25 b, and25 c and the capacitor 31 in the travel direction T of the vehicle V isalso one preferred embodiment of the invention.

(6) A case where the rotary electric machine-connection terminals 25 a,25 b, and 25 c are sequentially arrayed in the direction perpendicularto the rotating shaft 3 a of the rotary electric machine 3 and aredisposed so that the end portions of the rotary electricmachine-connection terminals corresponding to +X direction side arealigned with each other has been described by way of example in theabove-mentioned embodiment. However, the embodiment of the invention isnot limited thereto. That is, for example, a structure where the rotaryelectric machine-connection terminals 25 a, 25 b, and 25 c aresequentially arrayed in a direction crossing (inclined with respect to)the rotating shaft 3 a of the rotary electric machine 3 and the endportions of the rotary electric machine-connection terminalscorresponding to +X direction side are disposed so as to be lined up inthe shape of a straight line in the direction crossing (inclined withrespect to) the rotating shaft 3 a of the rotary electric machine 3 isalso one preferred embodiment of the invention. Further, in regard tothe positions of the respective end portions of the rotary electricmachine-connection terminals 25 a, 25 b, and 25 c corresponding to +Xdirection side, a structure where the end portions of the rotaryelectric machine-connection terminals are disposed so that a virtualline sequentially connecting the end portions of the rotary electricmachine-connection terminals from one side toward the other side in theY direction has the shape of a broken line is also one preferredembodiment of the invention.

(7) A case where a direction in which the upper and lower stage arms ofeach of the legs are connected to each other is the direction along theX direction and the three legs are sequentially arrayed in the Ydirection has been described by way of example in the above-mentionedembodiment. However, the embodiment of the invention is not limitedthereto. That is, for example, a structure where a direction in whichthe upper and lower stage arms of each of the legs are connected to eachother is a direction along the Y direction and the three legs aresequentially arrayed in the X direction is also one preferred embodimentof the invention.

(8) A case where the upper and lower stage arms are disposed so that thelongitudinal direction of each of the upper and lower stage arms is thedirection along the X direction has been described by way of example inthe above-mentioned embodiment. However, the embodiment of the inventionis not limited thereto. That is, for example, a structure where theupper and lower stage arms are disposed so that the longitudinaldirection of each of the upper and lower stage arms is the directionalong the Y direction is also one preferred embodiment of the invention.

(9) A case where the heat dissipating fins 11 b are provided on the sideopposite to the vehicle drive device 62 and the rotary electric machine3 with respect to the element placing surface 11 a (on the upper side inthe vertical direction) has been described by way of example in theabove-mentioned embodiment. However, the embodiment of the invention isnot limited thereto. That is, for example, a structure where the heatdissipating fins 11 b are provided on the same side as the vehicle drivedevice 62 and the rotary electric machine 3 with respect to the elementplacing surface 11 a (on the lower side in the vertical direction) isalso one preferred embodiment of the invention.

(10) A case where the extending direction of the heat dissipating fins11 b is set to the direction along the travel direction T of the vehicleV and the capacitor 31 is disposed adjacent to the heat dissipating fins11 b on the rear side in the travel direction T of the vehicle V inorder to use travel wind generated due to the travel of the vehicle Vhas been described by way of example in the above-mentioned embodiment.However, the embodiment of the invention is not limited thereto. Thatis, for example, a structure where the extending direction of the heatdissipating fins 11 b is set to a direction crossing the traveldirection T of the vehicle V (including a direction perpendicular to thetravel direction T of the vehicle V) when the capacitor 31 is disposedadjacent to the heat dissipating fins 11 b on the rear side in thetravel direction T of the vehicle V is also one preferred embodiment ofthe invention. Alternatively, the extending direction of the heatdissipating fins 11 b or the disposition position of the capacitor 31may also be set regardless of the travel direction T of the vehicle V.For example, when a vehicle V is provided with a fan for air-cooling(air-cooling fan), the extending direction of the heat dissipating fins11 b is set along the flow direction of cooling air generated by theair-cooling fan and the capacitor 31 is disposed adjacent to the heatdissipating fins 11 b on the downstream side of the cooling air is alsoone preferred embodiment of the invention.

(11) A case where the inverter device 1 is mounted on the vehicle V soas to be integrated with the vehicle drive device 62 and the rotaryelectric machine-connection terminals 25 a, 25 b, and 25 c are disposedso as to overlap the coils 3 b when seen in the radial direction of therotary electric machine 3 has been described by way of example in theabove-mentioned embodiment. However, the embodiment of the invention isnot limited thereto. That is, for example, a structure where the rotaryelectric machine-connection terminals 25 a, 25 b, and 25 c are disposedat different positions without overlapping the coils 3 b when seen inthe radial direction of the rotary electric machine 3 is also onepreferred embodiment of the invention. Further, a structure where thevehicle drive device 62 and the inverter device 1 are mounted on thevehicle V so as to be physically separated from each other is also onepreferred embodiment of the invention.

(12) A case where the invention is applied to the inverter device 1 of asystem controlling the rotary electric machine 3 functioning as adriving power source of the hybrid vehicle V has been described by wayof example in the above-mentioned embodiment. However, the embodiment ofthe invention is not limited thereto. That is, for example, theinvention may also be applied to an inverter device that controls amotor provided in an air conditioner; an electric power controller(power conditioner) that converts electric power between DC power, whichis generated by a private power generation system such as a solar powergeneration system or a fuel cell, and AC power that is supplied from acommercial electric power system; and the like. In this case, the motoror the commercial electric power system corresponds to an “externaldevice” of the invention.

(13) Even in regard to other structures, the embodiment disclosed inthis specification is illustrative in all aspects and the embodiment ofthe invention is not limited thereto. That is, structures that are notdisclosed in claims of this application may be appropriately modifiedwithin a range that does not depart from the object of the invention.

The invention may be used suitable for an inverter device including aplurality of switching elements that convert electric power between DCpower and AC power, a base plate that includes an element placingsurface on which these plurality of switching elements are placed, ACterminals that input and output AC power to and from an external device,and a capacitor that smoothes DC power.

What is claimed is:
 1. An inverter device including a plurality ofswitching elements that convert electric power between DC power and ACpower, a base plate that includes an element placing surface on whichthe plurality of switching elements are placed, AC terminals throughwhich AC power is input and output to and from an external device andwhich are electrically connected to the switching elements, and acapacitor that smoothes DC power, wherein the AC terminals are disposedso as to protrude from the base plate in a predetermined first referencedirection in plan view seen in a direction perpendicular to the elementplacing surface, the capacitor is disposed in a capacitor dispositionarea that is set in a rectangular shape in the plan view, and thecapacitor disposition area is set so that long sides of the rectangularshape are parallel to the first reference direction in the plan view,and is set adjacent to a base disposition area, in which the base plateand the AC terminals are disposed, in a second reference direction thatis a direction perpendicular to the first reference direction.
 2. Theinverter device according to claim 1, further comprising: a controlboard that is provided with at least a drive circuit for the switchingelements, wherein the control board is adjacent to both the capacitordisposition area and the base disposition area in a perpendicularreference direction, which is a direction perpendicular to the elementplacing surface, and is disposed at a position overlapping both thecapacitor disposition area and the base disposition area in the planview.
 3. The inverter device according to claim 2, wherein the length ofthe capacitor disposition area in the first reference direction is setso as to be longer than the length of the base plate in the firstreference direction, and the AC terminals are disposed in an areaoverlapping the capacitor disposition area when seen in the secondreference direction.
 4. The inverter device according to claim 3,wherein heat dissipating fins are provided on the side of the base plateopposite to the element placing surface, and a connecting support, whichsupports electrical connection members electrically connecting at leastthe switching elements to the AC terminals, is provided on the same sideof the base plate as the element placing surface, the base dispositionarea is set so as to include disposition areas of the heat dissipatingfins and the connecting support, and the length and position of thecapacitor disposition area in a perpendicular reference direction, whichis a direction perpendicular to the element placing surface, are set soas to correspond with the length and position of the base dispositionarea in the perpendicular reference direction.
 5. The inverter deviceaccording to claim 4, wherein the length and position of the capacitordisposition area in the first reference direction are set so as tocorrespond with the length and position of the base disposition area inthe first reference direction.
 6. The inverter device according to claim2, further comprising: power supply terminals through which DC power isinput and output to and from a DC power source; DC terminals throughwhich DC power is input and output to and from the switching elements;and capacitor connecting members that electrically connect the powersupply terminals to the DC terminals through the capacitor, wherein thecontrol board is further provided with a voltage detecting circuit thatdetects a voltage between both electrodes of the capacitor, and branchconnection portions, which are branched from the capacitor connectingmembers and extend in the perpendicular reference direction, areconnected to the voltage detecting circuit while passing through thecontrol board.
 7. The inverter device according to claim 6, wherein thepower supply terminals and the DC terminals are disposed at positionsthat are different in the first reference direction andpoint-symmetrical to each other with respect to the center of gravity ofthe shape of the capacitor disposition area in the plan view.
 8. Theinverter device according to claim 5, wherein the plurality of switchingelements form an inverter circuit, the inverter circuit has a three-legstructure including three legs that include switching elements formingupper stage arms connected to the side of a positive electrode andswitching elements forming lower stage arms connected to the side of anegative electrode, and a direction in which the upper and lower stagearms of each of the legs are connected to each other is a directionalong the first reference direction, and the three legs are sequentiallyarrayed in the second reference direction.
 9. The inverter deviceaccording to claim 8, wherein the upper and lower stage arms aredisposed so that a longitudinal direction of each of the upper and lowerstage arms is a direction along the first reference direction.
 10. Theinverter device according to claim 9, wherein the external device is arotary electric machine as a driving power source of a vehicle, heatdissipating fins are provided on the side of the base plate opposite tothe element placing surface, and an extending direction of the heatdissipating fins, which extend in the shape of a flat plate, is set soas to be a direction along a travel direction of the vehicle, and thecapacitor is disposed adjacent to the heat dissipating fins on the rearside in the travel direction of the vehicle.
 11. The inverter deviceaccording to claim 10, wherein a plurality of AC phase-terminals areprovided as the AC terminals, and the plurality of AC phase-terminalsare sequentially arrayed in the second reference direction, and thesecond reference direction is a direction perpendicular to a rotatingshaft of the rotary electric machine, and the plurality of ACphase-terminals are disposed so as to overlap coils of the rotaryelectric machine when seen in a radial direction of the rotary electricmachine.
 12. The inverter device according to claim 10, wherein the heatdissipating fins are provided on the side opposite to the rotaryelectric machine with respect to the element placing surface.
 13. Theinverter device according to claim 1, wherein the length of thecapacitor disposition area in the first reference direction is set so asto be longer than the length of the base plate in the first referencedirection, and the AC terminals are disposed in an area overlapping thecapacitor disposition area when seen in the second reference direction.14. The inverter device according to claim 1, wherein heat dissipatingfins are provided on the side of the base plate opposite to the elementplacing surface, and a connecting support, which supports electricalconnection members electrically connecting at least the switchingelements to the AC terminals, is provided on the same side of the baseplate as the element placing surface, the base disposition area is setso as to include disposition areas of the heat dissipating fins and theconnecting support, and the length and position of the capacitordisposition area in a perpendicular reference direction, which is adirection perpendicular to the element placing surface, are set so as tocorrespond with the length and position of the base disposition area inthe perpendicular reference direction.
 15. The inverter device accordingto claim 1, wherein the length and position of the capacitor dispositionarea in the first reference direction are set so as to correspond withthe length and position of the base disposition area in the firstreference direction.
 16. The inverter device according to claim 1,wherein the plurality of switching elements form an inverter circuit,the inverter circuit has a three-leg structure including three legs thatinclude switching elements forming upper stage arms connected to theside of a positive electrode and switching elements forming lower stagearms connected to the side of a negative electrode, and a direction inwhich the upper and lower stage arms of each of the legs are connectedto each other is a direction along the first reference direction, andthe three legs are sequentially arrayed in the second referencedirection.
 17. The inverter device according to claim 1, wherein theexternal device is a rotary electric machine as a driving power sourceof a vehicle, heat dissipating fins are provided on the side of the baseplate opposite to the element placing surface, and an extendingdirection of the heat dissipating fins, which extend in the shape of aflat plate, is set so as to be a direction along a travel direction ofthe vehicle, and the capacitor is disposed adjacent to the heatdissipating fins on the rear side in the travel direction of thevehicle.
 18. The inverter device according to claim 2, wherein heatdissipating fins are provided on the side of the base plate opposite tothe element placing surface, and a connecting support, which supportselectrical connection members electrically connecting at least theswitching elements to the AC terminals, is provided on the same side ofthe base plate as the element placing surface, the base disposition areais set so as to include disposition areas of the heat dissipating finsand the connecting support, and the length and position of the capacitordisposition area in a perpendicular reference direction, which is adirection perpendicular to the element placing surface, are set so as tocorrespond with the length and position of the base disposition area inthe perpendicular reference direction.
 19. The inverter device accordingto claim 2, wherein the length and position of the capacitor dispositionarea in the first reference direction are set so as to correspond withthe length and position of the base disposition area in the firstreference direction.
 20. The inverter device according to claim 2,wherein the plurality of switching elements form an inverter circuit,the inverter circuit has a three-leg structure including three legs thatinclude switching elements forming upper stage arms connected to theside of a positive electrode and switching elements forming lower stagearms connected to the side of a negative electrode, and a direction inwhich the upper and lower stage arms of each of the legs are connectedto each other is a direction along the first reference direction, andthe three legs are sequentially arrayed in the second referencedirection.